Spandex fiber reacted with isocyanato group containing siloxane

ABSTRACT

SPANDEX FIBERS ARE DISCLOSED WHICH HAVE REACTED THEREWITH A LUBRICATING FINISH WHICH IS A SILOXANE HAVING THE AVERAGE GENERAL FORMULA   RN(CH3)3-NSI(/SI(CH3)2)X   (OSI(CH3)R)YOSI(CH3)3-NRN WHEREIN R IS A RADICAL ATTACHED TO THE SILICON ATOM VIA A NON-HYDROLYZABLE BOND AND CONTAINS AT LEAST ONE SUBSTITUENT THAT IS REACTIVE WITH THE SPANDEX FIBER, EACH N IS ZERO OR ONE, X AND Y ARE INTEGERS, AND THE RATIO OF SOLELY METHYL SUBSTITUTED SILICON ATOMS TO R SUBSTITUTED SILICON ATOMS IS IN THE RANGE OF 15-300:1. THESE SPANDEX FIBERS HAVE A PERMANENT FINISH WHICH IS NOT HARMFUL TO TE PHYSICAL PROPERTIES OF THE FIBER, WHICH WILL NOT MIGRATE, AND WHICH HAS A SIGNIFICANTLY REDUCED TENDENCY TO DISCOLOR THE FIBER.

April 3, 1973 J. K. CAMPBELL ET AL 3,725,000

SPANDEX FIBER REACTED WITH ISOCYANATO GROUP CONTAINING SILOXANE Filed March 22, 1971 mmomoumm INVENTORS JAMES K. CAMPBELL MARTIN C- MUSOLF y M FMMZ mwmE AGENT "United States Patent 3,725,000 SPANDEX FIBER REACTED WITH ISOCYANATO GROUP CONTAINING SILOXANE James K. Campbell and Martin C. Musolf, Midland,

xiclhm, assignors to Dow Corning Corporation, Midland,

Continuation-impart of abandoned application Ser. No. 548,387, May 11, 1966. This application Mar. 22, 1971, Ser. No. 127,034

Int. Cl. D06m 3/26; D06c 29/00 US. Cl. 8115.6 4 Claims ABSTRACT OF THE DISCLOSURE Spandex fibers are disclosed which have reacted therewith a lubricating finish which is a siloxane having the average general formula This application is a continuation-in-part of abandoned application Ser. No. 548,387, filed May 11, 1966.

This invention relates to an improved spandex fiber and to processes for making the improved spandex fiber.

It is well known that elastic yarns made of rubber or of a segmented elastomer, e.g. of the spandex type, cannot be processed if free from lubricating finish. Such elastic yarns have a greater tendency than do relatively inelastic yarns for adjacent filaments of the yarn to cohere and for the yarn to stick to other surfaces, which causes erratic running tensions. Talc has been the classic lubricant for yarns and filaments made of rubber, and it may also be used to lubricate spandex yarns and filaments. Talc, however, has many disadvantages as a lubricant. It presents a housekeeping nuisance as well as a dust hazard, since it is spattered around the area in which the yarn is finished and processed. Moreover, talc-coated yarns or filaments give rise to serious abrasion problems both on spinning machines and on processing equipment.

Oils would appear to be attractive substitutes for talc for the purpose of overcoming these disadvantages. However, it has been found that oils are not without their own disadvantages. For example, the oils tend to migrate from the fiber surface, some oils have a detrimental effect on the physical properties of the fiber, and the oils tend to foster discoloration of the fiber.

It has been suggested that a satisfactory finish for spandex yarns and filaments can be made from a textile oil, such as mineral oil or polydimethylsiloxane oils, by dispersing therein finely-divided particles of certain metal soaps. These finishes also have disadvantages, in particular a tendency for the dispersed solids to settle in the finish troughs, and to the building up of deposits on yarn guides and needles in knitting machines and other processing equipment for the elastic yarns and filaments. Moreover, they too tend to migrate and cause discoloration of the fibers.

It is an object of this invention to provide an improved spandex fiber having a permanent finish which is not harmful to the physical properties of the fiber, which will not migrate, and which has a significantly reduced tendency to discolor the fiber. Another object of this invenice tion is to provide a new lubricating finish for spandex fibers. Still another object is to provide processes for making improved spandex fibers. Other objects and advantages of this invention will be apparent from the gicire detailed description and examples which are found e ow.

More specifically, this invention relates to a spandex fiber which has had reacted therewith a lubricating finish which is a siloxane having the average general formula R is a radical attached to the silicon atom via a nonhydrolyzable bond and contains at least one substituent that is reactive with the spandex fiber, each n is zero or one,

x and y are integers, and the ratio of solely methyl substituted silicon atoms to R substituted silicon atoms is in the range of 15-300: 1.

In particular this invention relates to a spandex fiber having chemically bound thereto a lubricating finish which is a siloxane having the average general formula wherein each n is zero or one, x and y are integers, the ratio of solely methyl substituted silicon atoms to R substituted silicon atoms is in the range of 15-300: 1, R is a radical of the structure -R-X..-R ,(O 1NH).,-R' and is attached to the silicon atom via a non-hydrolyza ble silicon to carbon bond, in said R radical R is an alkylene radical containing from 1 to 18 carbon atoms, X is a sulfur or oxygen atom and is attached to the R radical via a carbon to sulfur or carbon to oxygen bond, a is zero or one, R" is a divalent or trivalent radical composed of carbon and hydrogen atoms or carbon, hydrogen and oxygen atoms, any oxygen atoms being present as ether linkage, there being a total of from 3 to 50 atoms in R, said R" being attached to X via a sulfur to carbon or oxygen to carbon bond, b is zero or one, 0 is one or two, the

radical being attached to the R" radical via a carbon to oxygen bond and when 0 is two, each 0 (OPJNH) unit is attached to a different carbon atom of R", when a is zero then b is zero and c is one, when b is zero then a is zero and c is one, when b is one and R" is divalent then a is one and c is one, when b is one and R" is trivalent then a is one and c is two, R' is a polyvalent hydrocarbon radical selected from the group consisting of aliphatic, aromatic and combinations of aliphatic and aromatic radicals, R being free of aliphatic unsaturation and containing from 3 to 30 carbon atoms, R' being attached by one valence to the (OCNH) unit via a nitrogen to carbon bond, R containing at least one substituent that is reactive with the spandex fiber which substituent is selected from the group consisting of the isocyanato, amino, hydroxyl and mercapto groups, the number of such substituents corresponding to the remaining valences of R, and the lubricating finish being chemically bound to the spandex fiber as a result of the reaction between the substituents of the R portion of the R radical of the siloxane with the isocyanato and/r hydroxyl groups present on the spandex fiber.

This invention also relates to an improvement in a process for making spandex fibres which comprises incorrating as part of the fibers a siloxane having the average general formula wherein R is a radical attached to the silicon atom via a non-hydrolyzable bond and contains at least one substituent that is reactive with the spandex fiber components, each n is zero or one, x and y are integers, and the ratio of solely methyl substituted silicon atoms to R substituted silicon atoms is in the range of -300: 1.

This invention further relates to a process which comprises applying to a spandex fiber a siloxane having the average general formula wherein R is a radical attached to the silicon atom via a non-hydrolyzable bond and contains at least one substituent that is reactive with the spandex fiber, each n is zero or one, x and y are integers, and the ratio of solely substituted silicon atoms to R substituted silicon atoms is in the range of 15-30021.

In particular this invention relates to a process which comprises applying to a spandex fiber a siloxane having the average general formula wherein each n is zero or one, x and y are integers, the ratio of solely methyl substituted silicon atoms to R substituted silicon atoms is in the range of 15-300z1, R is a radical of the structure and is attached to the silicon atom via a non-hydrolyzable silicon to carbon bond, in said R radical R is an alkylene radical containing from 1 to 18 carbon atoms, X is a sulfur or oxygen atom and is attached to the R radical via a carbon to sulfur or carbon to oxygen bond, a is zero or one, R" is a divalent or trivalent radical composed of carbon and hydrogen atoms or carbon, hydrogen and oxygen atoms, any oxygen atoms being present as ether linkages, there being a total of from 3 to 50 atoms in R", said -R" being attached to X via a sulfur to carbon or oxygen to carbon bond, b is zero or one, c is one or two, the

radical being attached to the R" radical via a carbon to oxygen bond and when 0 is two, each 0 o ibNH unit is attached to a different carbon atom of R", when a is zero then b is zero and c is one, when b is zero then a is zero and c is one, when b is one and R" is divalent then a is one and c is one, when b is one and R is trivalent then a is one and c is two, R' is a polyvalent hydrocarbon radical selected from the group consisting of aliphatic, aromatic and combinations of aliphatic and aromatic radicals, R' being free of aliphatic unsaturation and containing from 3 to 30 carbon atoms, R being attached by one valence to the o obNH unit via a nitrogen to carbon bond, R" containing at least one substituent that is reactive with the spandex fiber which substituent is selected from the group consisting of the isocyanato, amino, hydroxyl and mercapto groups, the number of such substitutents corresponding to the remaining valences of R", and the lubricating finish being chemically bound to the spandex fiber as a result of the reaction between the substituents of the R' portion of the R radical of the siloxane with the isocyanato and/or hydroxyl groups present on the spandex fiber.

A spandex fiber or material as referred to herein is, as defined by the Federal Trade Commission under the Textile Fiber Products Identification Act of 1960, a manufactured fiber in which the fiber-forrning substance is a long chain synthetic elastomer comprised of at least percent by weight of a segmented polyurethane. Spandexes are well known in the art and are described in detail numerous places in the literature and hence will not be discussed further here.

The siloxanes useful in treating spandex fibers in accordance with the processes of this invention and which react therewith to form the improved spandex fibers claimed herein have the formulae set forth above. One critical limitation on the siloxanes is the presence of the radical R. This radical must be non-hydrolyzable, that is, it must be attached to the silicon atom via a silicon to carbon (SiC) bond. The R radical must also contain at least one substituent which is reactive with spandex fibers. This substituent might also be described as an isocyanate reactive group. Specific examples of such substituents include the isocyanate, amine, hydroxyl and mercaptan groups. These reactive groups are essential in that they are believed to cause a chemical bond between the siloxane and spandex fiber which, among other things, is believed to be responsible for the non-migrating characteristic of the resulting finish. Other than these considerations, the radical R can contain any other substituents or linkages which are compatible with the essential spandex reactive substituents and which are not detrimental to the spandex fiber itself. It is preferable to have at least two R radicals per siloxane molecule.

As defined above the R radical can also be defined as having the structure 0 RX,-R" O i JNH) R In this structure R is an alkylene radical containing from 1 to 18 carbon atoms, preferably 2 to 6 carbon atoms. By Way of illustration R can be a methylene, ethylene, propylene, isopropylene, butylene, isobutylene, hexylene, octylene, decylene, dodecylene, or octadecylene radical. The symbol X represents either a sulfur or oxygen atom. There can be zero or one X's, that is a is zero or one.

The R radical is either a divalent or trivalent radical composed of carbon and hydrogen atoms or carbon, hydrogen and oxygen atoms, any oxygen atoms being present as ether linkages. There is a total of 3 to 50 atoms of all kinds in the R" radical. The R" radical is attached to X via sulfur to carbon bond when X is a sulfur atom and via an oxygen to carbon bond when X is an oxygen atom. Illustrative of suitable R" radicals are the -CH (CH --CH CH(CH CH2- CH2 (IHCHz- CHmO CH1 43 0111 and The symbol c defines the number of urethane o (or...)

linkages present which can be one or two. The urethane linkage or unit is attached to the R" radical via a carbon to oxygen bond. Where there are two radicals present they are attached to dififerent carbon atoms of R".

As further limitations on the structure of the R radical, when a is zero then b is zero and c is one. Conversely, when b is zero then a is zero and c is one. Also, when b is one and R" is divalent then a is one and c is one. Further, when b is one and R is trivalent then a is one and c is two.

The terminal portion of the R radical structure is R'" which is a polyvalent hydrocarbon radical selected from the group consisting of aliphatic, aromatic and combinations of aliphatic and aromatic radicals. R" is free from aliphatic unsaturation and contains from 3 to 30 carbon atoms. The R' radical is attached by one valence to the unit via a nitrogen to carbon bond. Of course, when there units, i.e. when is two, there will be an R" radical attached to each such unit. The remaining valences of the R radical contain a substituent that is reactive with the spandex fiber which substituent is selected from the group consisting of the isocyanato, amino, hydroxyl and mercapto groups. These substituents react with the hydroxyl and/or isocyanato groups, primarily the latter of the spandex fibers whereby the siloxane finish becomes chemically bound to the spandex fiber.

Another critical limitation on the siloxane is the ratio of the solely or wholly methyl substituted silicon atoms to the R substituted silicon atoms. If this ratio falls below about 15:1, the resulting fiber exhibits generally poor and erratic lubricity. Also, in the case of isocyanate substituted R radicals, bad discoloring (yellowing) of the fiber tends to occur below this ratio. When this ratio exceeds about 300:1 discoloration becomes a problem again, apparently due to an insufiicient amount of reaction between the siloxane and the fiber. Preferably this ratio lies in the range of 30-100: 1.

As can readily be seen, the values of n, x and y determine what the above ratio of solely methyl substituted silicon atoms to R substituted silicon atoms actually is.

It is preferred that the siloxane employed be a fluid for ease of handling and application. Highly viscous or solid materials can be used but generally must be applied in a suitable carrier such as the common aliphatic, aromatic and chlorinated hydrocarbon solvents. The amount of siloxane applied and reacted with the spandex fiber should usually be at least 0.2 percent by weight, based on the weight of the fiber, in order to obtain satisfactory results; and although there appears to be no limit on how much of the siloxane that can be used, more than 5 percent by weight would not be practical, would not provide any added benefit, and would not be economical. It is preferred that 0.5 to 2.5 percent by weight of the siloxane be used.

While the siloxane employed herein are defined generally by the above formula, it is understood that there can be present some small amounts of CH SiO and SiO siloxane units in the structure. Also, in some instances, some of the methyl radicals can be replaced by longer chain alkyl radicals (up to about 18 carbon atoms in length) to promote compatibility with solvents or other additives. Generally speaking, less than five mol percent of these other units should be present.

The improved spandex fibers of this invention can b produced in many ways. For example, the siloxane can be applied to the formed spandex fiber at any point or combination of points up to and including just prior to spooling. Application can be by means well known in the art such as spraying, padding or dipping. When the siloxane is applied to the formed fiber, it is desirable, for best results, to heat the fiber briefiy after the siloxane has been applied to promote its reaction with the fiber. Generally speaking, heating for about 30 to seconds at about 300 F. will be adequate. A catalyst such as an organotin compound, for example stannous octoate, can also be employed to assist in reacting the siloxane and the fiber. It is preferred that the reactive substituent on the R radical be an isocyanate when the siloxane is applied to a formed spandex fiber.

Alternative processes for preparing the improved spandex fibers of this invention include the reaction of the siloxane with the spandex fiber components in the spinning solution or in the melt prior to formation of the fiber by extrusion. In these applications the siloxanes with R radicals containing amine, hydroxyl and mercaptan reactive substituents can find special utility.

It has also been discovered in accordance with this invention that the improved spandex fibers can be obtained by employing a blend of the above defined siloxane with mineral oil or a waxy siloxane polymer containing dimethylsiloxane units and methylalkylsiloxane units (the alkyl containing an average of at least 14 carbon atoms). A detailed description of the waxy siloxane polymers can be found in US. patent application Ser. No. 413,304 filed Nov. 23, 1964, which is now US. Pat. 3,423,235, the disclosure of which is incorporated herein by reference. Generally speaking, the mineral oil or waxy siloxane polymer can constitute up to about 90 percent by Weight of the total finish composition. However, for best results these materials should constitute only a minor portion of the composition, preferably less than about 35 percent.

Now in order that those skilled in the art may better understand how the present invention can be practiced, the following examples are given by way of illustration and not by way of limitation. All percents referred to herein are on a weight basis.

In the examples below, the spandex fibers used were commercially available materials obtained from various fiber manufacturers. Precise control of the amount of the siloxane applied to the fiber was achieved by metering it onto the individual fibers as they passed over a capillary opening. The xylene carrier used was driven off using a drum dryer prior to spooling the fiber for testing. The spandex fibers lubricated with the siloxane were then stored at 52 percent relative humidity and 76 (F. for a minimum of four hours before being evaluated.

The fibers were evaluated for fiber to guide friction on the friction analyzer using the arrangement shown diagrammatically in the drawing. In this test the fiber passes over a free wheeling pulley, slides around three stationary guides made of steel or ceramic and then passes over another free wheeling pulley. The friction is measured by means of strain gauges at the pulleys, the gauges being connected to a recorder. Standard operating fiber velocity of 18 yards per minute was used for evaluating the fiber to guide friction. The results are reported as the greatest deviation from the base line on the recorder.

7 EXAMPLE 1 A siloxane of the average general formula NCO CH; OH: I

8 EXAMPLE 3 The siloxanes below were prepared and applied to was prepared by reacting allyloxypropanol with the apspandex fiber (A) employing the procedure of Example OCN l, and then the fiber evaluated for fiber to guide friction. The amount of siloxane applied was 1 percent in each instance. The test results are set forth in the table following the list of siloxanes.

NCO

( 2): 3): CH; O

OCN

NCO

(CH3)2 (CH3),

| 0 on, o I

I cut-Gumbo cncmo cuminosuonnzlaosucnmo CH CH-O dung-on,

C CH2 NCOv NCO

on, o

I (CHmSilOSMCHmI osi onmo Gracia-o dNnO-om osiwm Relative friction on guides Steel Ceramic Spandex fiber Manufacturer Siloxane Globe-m $353311: 3 3:?

(B). Lycra-.." DuPont ..{gg g i N0- 2.5 2.5

(C). Numa. American Cyanamtd Yes" 2 L5 (D)... Vyrene U.S. Rubber gg g EXAMPLE 2 The procedure of Example 1 was repeated with spandex fiber (A) applying various amounts of the siloxane to the fiber. The results are set forth in the table below.

Relative friction on guides siloxane Steel Ceramie 3 2 3 2 2.5 percent. 3 2 5.0 percent 3. 5 2. 5

Relative friction on guides Siloxane Steel Ceramic l 280 denier fibers. 7 70 denier fibers.

EXAMPLE 4 Fiber (A) of Example 1 was evaluated to determine the effectiveness of the siloxane finish of this invention in preventing cohesion (blocking) of the fibers. This was done by winding about a /2 inch thickness of the fiber on a 1% inch diameter rod at a 2:1 stretch ratio. The wound fiber was allowed to stand at room temperature for 24 hours and then slit cross-sectionally with a razor blade. In this test if the finish provides adequate lubrication of the fibers upon slitting, they will unwind and separate showing no cohesion or blocking has taken place. If the finish does not provide adequate lubrication of the fibers, upon slitting they will not unwind or separate due to fiber cohesion or blocking. The fibers are visually evaluated and rated as to the degree of blocking. Also included in this valuation for purposes of comparison was fiber (A) which had been finished with mineral oil and polydimethylsiloxane oil. The test results are set forth in the table below.

Fiber finish: Blocking None Excessive. Mineral oil Do. Polydimethylsiloxane oil Some. Siloxane of Example 1 None. Blend of siloxane of Example 1 and 10% mineral oil Do.

1 Also causes discoloration of the fiber.

- EXAM PLE That which is claimed when the following siloxane? are Substituted for the 1. A spandex fiber having chemically bound thereto a siloxanes of the previous examples essentially equivalent results are obtained. (A) NCO (CHM 0 (CHahSii0suom):luosiuoHmSomGHcmo NHOcH,

images. 4 I'm (B) N00 N00 NCO 0 11:): CH: 0 (CH2): 0 omc-Nn owmhdu0simian):lnlo xcflmo Nfl-c-omlOdKCHmO NH-GCH,

(C) CH; O otmnoflmsitosiwmhmroduonmswnmo OHzCHzO NHwHmNGO OSi(OHa) C H CzHs mooNmcHmNoo NCO CH;

' a r oo CH: CH; O on,si( 0 suompmo sin CHmO omen-o ENHG-OHJO suonm) 4 8 EXAMPLE 6 lubricating finish which is a siloxane having the average general formula When the blends specified below are substituted for the finishes of the previous examples, essentially equivalent Rn(CH3)3nSi{oSi(CH3)2}x results are obtained. {OSi(CH3)R}YOSi(CH3)3-I1Rn (A) 80% siloxane (A) of Example 3 and 20% mineral wher ein each a m t' r 11 m1 bt' xan yaremegers, eraloo soeyme ySllSlg slloxane (D) of Example 3 and 35% mmeral tuted silicon atoms to R substituted silicon atoms is (C) 25% siloxane of Example 1 and 75% mineral oil m the range of 15400: 95% siloxane f Example 5 and 5% R is a radical with a structure selected from the group 22 45( 3)2 a)z 5 s)2 2a 4s menus I (E) 75% siloxane (B) of Example 3 and 25% i --R'- 0 NH R' When the siloxanes specified below are incorporated JJ R, into the spinning solution or melt of a spandex fiber, the improved spandex fibers of this invention are obtained. '-X

111N011, CH:NHCH,CH(CH;) omdi-tosuoflomuoo SiCHzCH(CHs)CHzNHCHzNH1 R is an alkylene radical containing from 1 to 18 wherein OSKCHIMNH X is a sulfur or oxygen atom and is attached to (D) CH8 the R radical via a carbon to sulfur or carbon a)z l Hz):lm{ g o Ha)a "(0 oxygen bond,

H 'R" is a radical composed of carbon and hydrogen atoms, or carbon, hydrogen and oxygen atoms,

( (CH3): any oxygen atoms being present as ether linkages, there being a total of from 3 to 50 atoms in R", said R being attached to X via a sulfur (F) OH to carbon or oxygen to carbon bond,

= Hg C(HSi)lO l ;(mH)!sC{ }OSi(CHs)2C1sHa1 R is a polyvalent hydrocarbon radical selected OSKCHMSH from the group consisting of aliphatic, aromatic C H HSCHzCH: i-l OSi(CHa): la10{ A O iCHzCHz SH 10 SlCH: GHzSH 11 12 and combinations of aliphatic and aromatic stituted silicon atoms to R substituted silicon atoms radicals, R being free of aliphatic unsaturation is in the range of 15-300: 1, and containing from 3 to 30 carbon atoms, R is a radical with a structure selected from the group R' being attached by one valence to the consisting of 0 (Ot'lNH) -R-(0 ylNH)R"' unit via a nitrogen to carbon bond, R containing at least one isocyanato substituent that is reactive with the spandex fiber, the number of such isocyanato substituents corresponding and to the remaining valences of R', and

the lubricating finish being chemically. bound to the E spandex fiber as a result of the reaction between the iso- O NH)R cyanato substituents of the R' portion of the R radical of the siloxane with the isocyanato and/or hydroxyl )OCNHPR,

groups present on the spandex fiber.

2. A spandex fiber as defined in claim 1 wherein the ratio of solely methyl substituted silicon atoms to R subwherein stituted silicon atoms is in the range of -100z1. 20 R is an alkylene radical containing from 1 to 18 3. A spandex fiber as defined in claim 2 wherein in the carbon atoms,

siloxane each n is one and y is zero. X is a sulfur or oxygen atom and is attached to the 4. A spandex fiber as defined in claim 3 in which the R radical via a carbon to sulfur or carbon to siloxane has the formula oxygen bond,

OCN 'NCO CHa (CH3): (CHs): CH;

O O I l l I I om-c-Nnlio cnonio (CH2)aSilOSi(CHa)2lm0 suonmo onion-o yJNH-O-CH;

5. A spandex fiber as defined in claim 2 wherein in the siloxane each n is zero.

6. A spandex fiber as defined in claim 5 in which the siloxane has the formula NCO CH3 CH3 0 (CHmSiKOSKCHzMras os ucnmocmon-o PJNEOCH; osuorrm 7. The spandex fiber as defined in claim 1 wherein a R" is a radical composed of carbon and hydrogen material selected from the group consisting of mineral oil atoms, or carbon, hydrogen and oxygen atoms, and waxy siloxane polymers is employed as part of the any oxygen atoms, being present as ether linkfinish. ages, there being a total of from 3 to 50 atoms 8. A process as defined in claim 14 where the ratio of in R", said R" being attached toX via a sulfur to solely methyl substituted silicon atoms to R substituted carbon or oxygen to carbon bond, silicon atoms is in the range of 30-10011. R' is a polyvalent hydrocarbon radical selected 9. A process as defined in claim 8 wherein in the from the group consisting of aliphatic, aromatic siloxane each n is one and y is zero. and combinations of aliphatic and aromatic 10. A process as defined in claim 9 in which the radicals, R being free of aliphatic unsaturasiloxane has the formula tion and containing from 3 to 30 carbon atoms,

CON

11. A process as defined in claim 8 wherein in the siloxane each n is zero.

12. A process as defined in claim 11 in which the siloxane has the formula N00 (311: (IJHa I (OHa)aSi{0Si(CHz)2lm- 0Si(CH1)a0CHzCHO( NH -CH; osiwm),

13. A process as defined in claim 14 wherein a material R" being attached by one valence to the selected from the group consisting of mineral oil and waxy siloxane polymers is employed as part of the finish. 14. A process which comprises applying to a spandex 0 fiber a siloxane having the average general formula (OLENH) Rn CH3 3-S1{OS1(CH3)2}6S. CH R OH R unit via a nitrogen to carbon bond, R" con- 1( 3) }Y l( taining at least one isocyanato substituent that wherein each is reactive with the spandex fiber, the number of nis zero or one, such isocyanato substituents corresponding to x and y are integers, the ratio of solely methyl subthe remaining valences of R, and

13 14 heating the fiber briefly after the application of the OTHER REFERENCES siloxane thereto, whereby a lubricating finish is chemically Pattarson et a1 Defi pub of SN 705,283, filed Feb.

bound to the spandex fiber as a result of the reaction be tween the isocyanato substituents of the R' portion of 1968 pubhshed on 1969' the R radical of the siloxane with the isocyanato and/or 5 GEORGE E LESMES, p i Examiner hydroxyl groups present on the spandex fiber. R. E. M ARTIN, JR, Assistant Examiner References Cited UNITED STATES PATENTS 3,296,063 1/1967 Chandler 10 117-1395 

